Smart processing of WWAN packets transmitted over WLAN

ABSTRACT

Certain aspects of the present disclosure relate to smart processing of wireless wide area network (WWAN) packets transmitted over wireless local area network (WLAN). According to certain aspects, a method for wireless communications by a user equipment (UE) capable of communicating via at least first and second radio access technologies (RATs) is provided. The method generally includes dynamically switching to a location, within the UE, as an anchor point for processing packets based, at least in part, on operating states of the first and second RATs and routing packets received via at least one of the first and second RATs to the dynamically switched location of the anchor point.

BACKGROUND

Field of the Disclosure

Aspects of the present disclosure relate generally to wirelesscommunication systems, and more particularly, to smart processing ofwireless wide area network (WWAN) packets transmitted over wirelesslocal area network (WLAN).

Description of Related Art

Wireless communication networks are widely deployed to provide variouscommunication services such as voice, video, packet data, messaging,broadcast, etc. These wireless networks may be multiple-access networkscapable of supporting multiple users by sharing the available networkresources. Examples of such multiple-access networks include CodeDivision Multiple Access (CDMA) networks, Time Division Multiple Access(TDMA) networks, Frequency Division Multiple Access (FDMA) networks,Orthogonal FDMA (OFDMA) networks, and Single-Carrier FDMA (SC-FDMA)networks.

A wireless communication network may include a number of eNodeBs thatcan support communication for a number of user equipments (UEs). A UEmay communicate with an eNodeB via the downlink and uplink. The downlink(or forward link) refers to the communication link from the eNodeB tothe UE, and the uplink (or reverse link) refers to the communicationlink from the UE to the eNodeB.

SUMMARY

The systems, methods, and devices of the disclosure each have severalaspects, no single one of which is solely responsible for its desirableattributes. Without limiting the scope of this disclosure as expressedby the claims which follow, some features will now be discussed briefly.After considering this discussion, and particularly after reading thesection entitled “Detailed Description” one will understand how thefeatures of this disclosure provide advantages that include improvedcommunications between access points and stations in a wireless network.

Techniques for smart processing of wireless wide area network (WWAN)packets (e.g., long term evolution (LTE) packets) transmitted overwireless local area network (WLAN) interface (e.g., a WiFi interface)are described herein.

In an aspect, a method for wireless communications by a user equipment(UE) capable of communicating via at least first and second radio accesstechnologies (RATs) is provided. The method generally includesdynamically switching a location, within the UE, as an anchor point forprocessing packets based, at least in part, on operating states of thefirst and second RATs, and routing packets received via at least one ofthe first and second RATs to the dynamically selected location of theanchor point.

In another aspect, an apparatus for wireless communications by a UEcapable of communicating via at least first and second RATs is provided.The apparatus generally includes at least one processor configured to:dynamically switch to a location, within the UE, as an anchor point forprocessing packets based, at least in part, on operating states of thefirst and second RATs, and route packets received via at least one ofthe first and second RATs to the dynamically switched location of theanchor point; and a memory coupled with the at least one processor.

In yet another aspect, an apparatus for wireless communications by a UEcapable of communicating via at least first and second RATs is provided.The apparatus generally includes means for dynamically switching alocation, within the UE, as an anchor point for processing packetsbased, at least in part, on operating states of the first and secondRATs, and means for routing packets received via at least one of thefirst and second RATs to the dynamically selected location of the anchorpoint.

In yet another aspect, a computer-readable medium having instructionsstored thereon, the instructions executable by a processor for wirelesscommunications by a UE capable of communicating via at least first andsecond RATs. The instructions generally include instructions fordynamically switching a location, within the UE, as an anchor point forprocessing packets based, at least in part, on operating states of thefirst and second RATs, and routing packets received via at least one ofthe first and second RATs to the dynamically selected location of theanchor point.

To the accomplishment of the foregoing and related ends, the one or moreaspects comprise the features hereinafter fully described andparticularly pointed out in the claims. The following description andthe annexed drawings set forth in detail certain illustrative featuresof the one or more aspects. These features are indicative, however, ofbut a few of the various ways in which the principles of various aspectsmay be employed, and this description is intended to include all suchaspects and their equivalents.

BRIEF DESCRIPTION OF THE DRAWINGS

So that the manner in which the above-recited features of the presentdisclosure can be understood in detail, a more particular description,briefly summarized above, may be had by reference to aspects, some ofwhich are illustrated in the appended drawings. It is to be noted,however, that the appended drawings illustrate only certain typicalaspects of this disclosure and are therefore not to be consideredlimiting of its scope, for the description may admit to other equallyeffective aspects.

FIG. 1 is a block diagram conceptually illustrating an example of atelecommunications system, in accordance with certain aspects of thepresent disclosure;

FIG. 2 is a block diagram conceptually illustrating an example of adownlink frame structure in a telecommunications system, in accordancewith certain aspects of the present disclosure;

FIG. 3 is a block diagram conceptually illustrating a design of an eNode B (eNB) and a user equipment (UE) configured, in accordance withcertain aspects of the present disclosure;

FIG. 4 illustrates an example subframe resource element mapping, inaccordance with certain aspects of the present disclosure.

FIG. 5 discloses a continuous carrier aggregation type, in accordancewith certain aspects of the present disclosure;

FIG. 6 discloses a non-continuous carrier aggregation type, inaccordance with certain aspects of the present disclosure;

FIG. 7 is a block diagram illustrating a method for controlling radiolinks in multiple carrier configurations, in accordance with certainaspects of the present disclosure;

FIG. 8 illustrates using multiflow to deliver simultaneous data streams,in accordance with certain aspects of the present disclosure;

FIG. 9 illustrates two reference cellular-WLAN interworkingarchitectures for a wireless local area network (WLAN) and a 3GPP eNBwith disjoint bearer routing, in accordance with certain aspects of thepresent disclosure;

FIG. 10 illustrates a data path in which the UE receives data packetsfrom the wireless wide area network (WWAN) and WLAN, where the data sinkis located at the Applications processor;

FIG. 11 illustrates a data path in which the UE receives data packetsfrom the WWAN and WLAN, where the data sink is located at the devicetethered;

FIG. 12 illustrates a data path in which the UE receives data from onlythe WWAN and where the data sink is located at the applicationsprocessor;

FIG. 13 illustrates a data path in which the UE receives data from onlythe WWAN and where the data sink is located at the modem processor;

FIG. 14 illustrates a data path in which the UE receives data from onlythe WLAN and where the data sink is located at the tethered equipment;

FIG. 15 illustrates a data path in which the UE receives data from onlythe WLAN and where the data sink is located at the applicationsprocessor;

FIG. 16 is a flow chart illustrating example operations for wirelesscommunications by a UE, in accordance with certain aspects of thepresent disclosure.

FIG. 16A illustrates example means capable of performing the operationsshown in FIG. 16, in accordance with certain aspects of the presentdisclosure.

FIG. 17 illustrates an example data path for an example systemconfiguration and operation parameters where the UE is activelycommunicating via WLAN, WWAN is inactive, and the sink is in theapplications processor, in accordance with certain aspects of thepresent disclosure.

FIG. 18 illustrates an example data path for an example systemconfiguration and operation parameters where the UE is activelycommunicating via WLAN, WWAN is inactive, and the sink is in a tetheredequipment, in accordance with certain aspects of the present disclosure.

FIG. 19 illustrates another example data path for the systemconfiguration and operation parameters where the UE is activelycommunicating via WLAN, WWAN is inactive, and the sink is in a tetheredequipment, in accordance with certain aspects of the present disclosure.

FIG. 20 illustrates an example data path for an example systemconfiguration and operation parameters where the UE is activelycommunicating via WLAN, WWAN is inactive, and a sink is in both thetethered equipment and the applications processor, in accordance withcertain aspects of the present disclosure.

FIG. 21 is an example truth table showing conditions for switchinganchor point locations, in accordance with certain aspects of thepresent disclosure;

FIG. 21A is an example truth table showing initial conditions and anchorpoint location, in accordance with certain aspects of the presentdisclosure;

FIG. 21B is an example truth table showing a soft change in conditionsfor switching anchor point locations, in accordance with certain aspectsof the present disclosure;

FIG. 22 is a call flow diagram illustrating example operations forswitching an anchor point location, in accordance with certain aspectsof the present disclosure; and

FIG. 23 is a flow chart illustrating example operations for switching ananchor point location, in accordance with certain aspects of the presentdisclosure.

To facilitate understanding, identical reference numerals have beenused, where possible, to designate identical elements that are common tothe figures. It is contemplated that elements disclosed in oneembodiment may be beneficially utilized on other embodiments withoutspecific recitation.

DETAILED DESCRIPTION

Techniques for smart processing of wireless wide area network (WWAN)packets (e.g., long term evolution (LTE) packets) transmitted overwireless local area network (WLAN) interface (e.g., a WiFi interface)are described herein. According to certain aspects, a user equipment(UE) capable of communicating via at least first and second radio accesstechnologies (RATs) may dynamically switch to a location, within the UE,as an anchor point for processing packet data convergence protocol(PDCP) data packets based, at least in part, on operating states of thefirst and second RATs (e.g., the destination of the data packets, thedirect connection between the location of the anchor point and thedestination of the data packets, efficiency, etc.). The location of theanchor point may be dynamically switched between the modem processor andthe applications processor, within the UE, using inter-processorcommunication between the modem processor and the applicationsprocessor. The UE may route packets received via at least one of thefirst and second RATs to the dynamically switched location of the anchorpoint.

The detailed description set forth below, in connection with theappended drawings, is intended as a description of variousconfigurations and is not intended to represent the only configurationsin which the concepts described herein may be practiced. The detaileddescription includes specific details for the purpose of providing athorough understanding of the various concepts. However, it will beapparent to those skilled in the art that these concepts may bepracticed without these specific details. In some instances, well-knownstructures and components are shown in block diagram form in order toavoid obscuring such concepts.

The techniques described herein may be used for various wirelesscommunication networks such as CDMA, TDMA, FDMA, OFDMA, SC-FDMA andother networks. The terms “network” and “system” are often usedinterchangeably. A CDMA network may implement a radio technology such asUniversal Terrestrial Radio Access (UTRA), cdma2000, etc. UTRA includesWideband CDMA (WCDMA) and other variants of CDMA. cdma2000 coversIS-2000, IS-95 and IS-856 standards. A TDMA network may implement aradio technology such as Global System for Mobile Communications (GSM).An OFDMA network may implement a radio technology such as Evolved UTRA(E-UTRA), Ultra Mobile Broadband (UMB), IEEE 802.11 (Wi-Fi), IEEE 802.16(WiMAX), IEEE 802.20, Flash-OFDMA, etc. UTRA and E-UTRA are part ofUniversal Mobile Telecommunication System (UMTS). 3GPP Long TermEvolution (LTE) and LTE-Advanced (LTE-A) are new releases of UMTS thatuse E-UTRA. UTRA, E-UTRA, UMTS, LTE, LTE-A and GSM are described indocuments from an organization named “3rd Generation PartnershipProject” (3GPP). cdma2000 and UMB are described in documents from anorganization named “3rd Generation Partnership Project 2” (3GPP2). Thetechniques described herein may be used for the wireless networks andradio technologies mentioned above as well as other wireless networksand radio technologies. For clarity, certain aspects of the techniquesare described below for LTE, and LTE terminology is used in much of thedescription below.

An Example Wireless Communications System

FIG. 1 shows a wireless communication network 100, in which aspects ofthe present disclosure may be performed. For example, the UE 120 may becapable of communicating via at least a first eNB 110 a and a second eNB110 b and may receive data packets from at least eNB 110 a and eNB 110b. The UE 120 may dynamically switch a location, within the UE 120, asan anchor point for processing the data packets received from the eNB110 (e.g., based on the various operating parameters). The UE 120 mayroute packets received from eNB 110 to the dynamically switched locationof the anchor point.

The wireless communications network 100 may be, for example, an LTEnetwork. The wireless network 100 may include a number of evolved NodeBs (eNodeBs) 110 and other network entities. An eNodeB may be a stationthat communicates with the UEs and may also be referred to as a basestation, an access point, etc. A Node B is another example of a stationthat communicates with the UEs.

Each eNodeB 110 may provide communication coverage for a particulargeographic area. In 3GPP, the term “cell” can refer to a coverage areaof an eNodeB and/or an eNodeB subsystem serving this coverage area,depending on the context in which the term is used.

An eNodeB may provide communication coverage for a macro cell, a picocell, a femto cell, and/or other types of cell. A macro cell may cover arelatively large geographic area (e.g., several kilometers in radius)and may allow unrestricted access by UEs with service subscription. Apico cell may cover a relatively small geographic area and may allowunrestricted access by UEs with service subscription. A femto cell maycover a relatively small geographic area (e.g., a home) and may allowrestricted access by UEs having association with the femto cell (e.g.,UEs in a Closed Subscriber Group (CSG), UEs for users in the home,etc.). An eNodeB for a macro cell may be referred to as a macro eNodeB.An eNodeB for a pico cell may be referred to as a pico eNodeB. An eNodeBfor a femto cell may be referred to as a femto eNodeB or a home eNodeB.In the example shown in FIG. 1, the eNodeBs 110 a, 110 b and 110 c maybe macro eNodeBs for the macro cells 102 a, 102 b and 102 c,respectively. The eNodeB 110 x may be a pico eNodeB for a pico cell 102x. The eNodeBs 110 y and 110 z may be femto eNodeBs for the femto cells102 y and 102 z, respectively. An eNodeB may support one or multiple(e.g., three) cells.

The wireless network 100 may also include relay stations. A relaystation is a station that receives a transmission of data and/or otherinformation from an upstream station (e.g., an eNodeB or a UE) and sendsa transmission of the data and/or other information to a downstreamstation (e.g., a UE or an eNodeB). A relay station may also be a UE thatrelays transmissions for other UEs. In the example shown in FIG. 1, arelay station 110 r may communicate with the eNodeB 110 a and a UE 120 rin order to facilitate communication between the eNodeB 110 a and the UE120 r. A relay station may also be referred to as a relay eNodeB, arelay, etc.

The wireless network 100 may be a heterogeneous network that includeseNodeBs of different types, e.g., macro eNodeBs, pico eNodeBs, femtoeNodeBs, relays, etc. These different types of eNodeBs may havedifferent transmit power levels, different coverage areas, and differentimpact on interference in the wireless network 100. For example, macroeNodeBs may have a high transmit power level (e.g., 20 Watts) whereaspico eNodeBs, femto eNodeBs and relays may have a lower transmit powerlevel (e.g., 1 Watt).

The wireless network 100 may support synchronous or asynchronousoperation. For synchronous operation, the eNodeBs may have similar frametiming, and transmissions from different eNodeBs may be approximatelyaligned in time. For asynchronous operation, the eNodeBs may havedifferent frame timing, and transmissions from different eNodeBs may notbe aligned in time. The techniques described herein may be used for bothsynchronous and asynchronous operation.

A network controller 130 may couple to a set of eNodeBs and providecoordination and control for these eNodeBs. The network controller 130may communicate with the eNodeBs 110 via a backhaul. The eNodeBs 110 mayalso communicate with one another, e.g., directly or indirectly viawireless or wireline backhaul.

The UEs 120 (e.g., 120 x, 120 y, etc.) may be dispersed throughout thewireless network 100, and each UE may be stationary or mobile. A UE mayalso be referred to as a terminal, a mobile station, a subscriber unit,a station, etc. A UE may be a cellular phone, a personal digitalassistant (PDA), a wireless modem, a wireless communication device, ahandheld device, a laptop computer, a cordless phone, a wireless localloop (WLL) station, a tablet, a netbook, a smart book, etc. A UE may beable to communicate with macro eNodeBs, pico eNodeBs, femto eNodeBs,relays, etc. In FIG. 1, a solid line with double arrows indicatesdesired transmissions between a UE and a serving eNodeB, which is aneNodeB designated to serve the UE on the downlink and/or uplink. Adashed line with double arrows indicates interfering transmissionsbetween a UE and an eNodeB.

LTE utilizes orthogonal frequency division multiplexing (OFDM) on thedownlink and single-carrier frequency division multiplexing (SC-FDM) onthe uplink. OFDM and SC-FDM partition the system bandwidth into multiple(K) orthogonal subcarriers, which are also commonly referred to astones, bins, etc. Each subcarrier may be modulated with data. Ingeneral, modulation symbols are sent in the frequency domain with OFDMand in the time domain with SC-FDM. The spacing between adjacentsubcarriers may be fixed, and the total number of subcarriers (K) may bedependent on the system bandwidth. For example, the spacing of thesubcarriers may be 15 kHz and the minimum resource allocation (called a‘resource block’) may be 12 subcarriers (or 180 kHz). Consequently, thenominal FFT size may be equal to 128, 256, 512, 1024 or 2048 for systembandwidth of 1.25, 2.5, 5, 10 or 20 megahertz (MHz), respectively. Thesystem bandwidth may also be partitioned into subbands. For example, asubband may cover 1.08 MHz (i.e., 6 resource blocks), and there may be1, 2, 4, 8 or 16 subbands for system bandwidth of 1.25, 2.5, 5, 10 or 20MHz, respectively.

FIG. 2 shows a down link frame structure used in LTE. The transmissiontimeline for the downlink may be partitioned into units of radio frames.Each radio frame may have a predetermined duration (e.g., 10milliseconds (ms)) and may be partitioned into 10 sub-frames withindices of 0 through 9. Each sub-frame may include two slots. Each radioframe may thus include 20 slots with indices of 0 through 19. Each slotmay include L symbol periods, e.g., 7 symbol periods for a normal cyclicprefix (as shown in FIG. 2) or 14 symbol periods for an extended cyclicprefix. The 2L symbol periods in each sub-frame may be assigned indicesof 0 through 2L−1. The available time frequency resources may bepartitioned into resource blocks. Each resource block may cover Nsubcarriers (e.g., 12 subcarriers) in one slot.

In LTE, an eNodeB may send a primary synchronization signal (PSS) and asecondary synchronization signal (SSS) for each cell in the eNodeB. Theprimary and secondary synchronization signals may be sent in symbolperiods 6 and 5, respectively, in each of sub-frames 0 and 5 of eachradio frame with the normal cyclic prefix, as shown in FIG. 2. Thesynchronization signals may be used by UEs for cell detection andacquisition. The eNodeB may send a Physical Broadcast Channel (PBCH) insymbol periods 0 to 3 in slot 1 of sub-frame 0. The PBCH may carrycertain system information.

The eNodeB may send a Physical Control Format Indicator Channel (PCFICH)in a portion of the first symbol period of each sub-frame, althoughdepicted in the entire first symbol period in FIG. 2. The PCFICH mayconvey the number of symbol periods (M) used for control channels, whereM may be equal to 1, 2 or 3 and may change from sub-frame to sub-frame.M may also be equal to 4 for a small system bandwidth, e.g., with lessthan 10 resource blocks. In the example shown in FIG. 2, M=3. The eNodeBmay send a Physical HARQ Indicator Channel (PHICH) and a PhysicalDownlink Control Channel (PDCCH) in the first M symbol periods of eachsub-frame (M=3 in FIG. 2). The PHICH may carry information to supporthybrid automatic retransmission (HARQ). The PDCCH may carry informationon uplink and downlink resource allocation for UEs and power controlinformation for uplink channels. Although not shown in the first symbolperiod in FIG. 2, it is understood that the PDCCH and PHICH are alsoincluded in the first symbol period. Similarly, the PHICH and PDCCH arealso both in the second and third symbol periods, although not .shownthat way in FIG. 2. The eNodeB may send a Physical Downlink SharedChannel (PDSCH) in the remaining symbol periods of each sub-frame. ThePDSCH may carry data for UEs scheduled for data transmission on thedownlink. The various signals and channels in LTE are described in 3GPPTS 36.211, entitled “Evolved Universal Terrestrial Radio Access(E-UTRA); Physical Channels and Modulation,” which is publiclyavailable.

The eNodeB may send the PSS, SSS and PBCH in the center 1.08 MHz of thesystem bandwidth used by the eNodeB. The eNodeB may send the PCFICH andPHICH across the entire system bandwidth in each symbol period in whichthese channels are sent. The eNodeB may send the PDCCH to groups of UEsin certain portions of the system bandwidth. The eNodeB may send thePDSCH to specific UEs in specific portions of the system bandwidth. TheeNodeB may send the PSS, SSS, PBCH, PCFICH and PHICH in a broadcastmanner to all UEs, may send the PDCCH in a unicast manner to specificUEs, and may also send the PDSCH in a unicast manner to specific UEs.

A number of resource elements may be available in each symbol period.Each resource element may cover one subcarrier in one symbol period andmay be used to send one modulation symbol, which may be a real orcomplex value. Resource elements not used for a reference signal in eachsymbol period may be arranged into resource element groups (REGs). EachREG may include four resource elements in one symbol period. The PCFICHmay occupy four REGs, which may be spaced approximately equally acrossfrequency, in symbol period 0. The PHICH may occupy three REGs, whichmay be spread across frequency, in one or more configurable symbolperiods. For example, the three REGs for the PHICH may all belong insymbol period 0 or may be spread in symbol periods 0, 1 and 2. The PDCCHmay occupy 9, 18, 32 or 64 REGs, which may be selected from theavailable REGs, in the first M symbol periods. Certain combinations ofREGs may be used for the PDCCH.

A UE may know the specific REGs used for the PHICH and the PCFICH. TheUE may search different combinations of REGs for the PDCCH. The numberof combinations to search is typically less than the number of allowedcombinations for the PDCCH. An eNodeB may send the PDCCH to the UE inany of the combinations that the UE will search.

A UE may be within the coverage of multiple eNodeBs. One of theseeNodeBs may be selected to serve the UE. The serving eNodeB may beselected based on various criteria such as received power, path loss,signal-to-noise ratio (SNR), etc.

FIG. 3 shows a block diagram of a design of a base station/eNodeB 110and a UE 120, which may be one of the base stations/eNodeBs and one ofthe UEs in FIG. 1. For a restricted association scenario, the basestation 110 may be the macro eNodeB 110 c in FIG. 1, and the UE 120 maybe the UE 120 y. The base station 110 may also be a base station of someother type. The base station 110 may be equipped with antennas 334 athrough 334 t, and the UE 120 may be equipped with antennas 352 athrough 352 r.

At the base station 110, a transmit processor 320 may receive data froma data source 312 and control information from a controller/processor340. The control information may be for the PBCH, PCFICH, PHICH, PDCCH,etc. The data may be for the PDSCH, etc. The processor 320 may process(e.g., encode and symbol map) the data and control information to obtaindata symbols and control symbols, respectively. The processor 320 mayalso generate reference symbols, e.g., for the PSS, SSS, andcell-specific reference signal. A transmit (TX) multiple-inputmultiple-output (MIMO) processor 330 may perform spatial processing(e.g., precoding) on the data symbols, the control symbols, and/or thereference symbols, if applicable, and may provide output symbol streamsto the modulators (MODs) 332 a through 332 t. Each modulator 332 mayprocess a respective output symbol stream (e.g., for OFDM, etc.) toobtain an output sample stream. Each modulator 332 may further process(e.g., convert to analog, amplify, filter, and upconvert) the outputsample stream to obtain a downlink signal. Downlink signals frommodulators 332 a through 332 t may be transmitted via the antennas 334 athrough 334 t, respectively.

At the UE 120, the antennas 352 a through 352 r may receive the downlinksignals from the base station 110 and may provide received signals tothe demodulators (DEMODs) 354 a through 354 r, respectively. Eachdemodulator 354 may condition (e.g., filter, amplify, downconvert, anddigitize) a respective received signal to obtain input samples. Eachdemodulator 354 may further process the input samples (e.g., for OFDM,etc.) to obtain received symbols. A MIMO detector 356 may obtainreceived symbols from all the demodulators 354 a through 354 r, performMIMO detection on the received symbols if applicable, and providedetected symbols. A receive processor 358 may process (e.g., demodulate,deinterleave, and decode) the detected symbols, provide decoded data forthe UE 120 to a data sink 360, and provide decoded control informationto a controller/processor 380.

On the uplink, at the UE 120, a transmit processor 364 may receive andprocess data (e.g., for the PUSCH) from a data source 362 and controlinformation (e.g., for the PUCCH) from the controller/processor 380. Thetransmit processor 364 may also generate reference symbols for areference signal. The symbols from the transmit processor 364 may beprecoded by a TX MIMO processor 366 if applicable, further processed bythe demodulators 354 a through 354 r (e.g., for SC-FDM, etc.), andtransmitted to the base station 110. At the base station 110, the uplinksignals from the UE 120 may be received by the antennas 334, processedby the modulators 332, detected by a MIMO detector 336 if applicable,and further processed by a receive processor 338 to obtain decoded dataand control information sent by the UE 120. The receive processor 338may provide the decoded data to a data sink 339 and the decoded controlinformation to the controller/processor 340.

The controllers/processors 340 and 380 may direct the operation at thebase station 110 and the UE 120, respectively. The processor 340 and/orother processors and modules at the base station 110 may perform ordirect, e.g., the execution of various processes for the techniquesdescribed herein. The processor 380 and/or other processors and modulesat the UE 120 may also perform or direct, e.g., the execution of thefunctional blocks illustrated in FIG. 7, and/or other processes for thetechniques described herein. The memories 342 and 382 may store data andprogram codes for the base station 110 and the UE 120, respectively. Ascheduler 344 may schedule UEs for data transmission on the downlinkand/or uplink.

In one configuration, the base station 110 includes means for generatinga compact Downlink Control Information (DCI) for at least one of uplink(UL) or downlink (DL) transmissions, wherein the compact DCI comprises areduced number of bits when compared to certain standard DCI formats;and means for transmitting the DCI. In one aspect, the aforementionedmeans may be the controller/processor 340, the memory 342, the transmitprocessor 320, the modulators 332, and the antennas 334 configured toperform the functions recited by the aforementioned means. In anotheraspect, the aforementioned means may be a module or any apparatusconfigured to perform the functions recited by the aforementioned means.In one configuration, the UE 120 includes means for receiving compactDownlink Control Information (DCI) for at least one of uplink (UL) ordownlink (DL) transmissions, wherein the DCI comprises a reduced numberof bits of a standard DCI format; and means for processing the DCI. Inone aspect, the aforementioned means may be the controller/processor380, the memory 382, the receive processor 358, the MIMO detector 356,the demodulators 354, and the antennas 352 configured to perform thefunctions recited by the aforementioned means. In another aspect, theaforementioned means may be a module or any apparatus configured toperform the functions recited by the aforementioned means.

FIG. 4 shows two exemplary subframe formats 410 and 420 for the downlinkwith the normal cyclic prefix. The available time frequency resourcesfor the downlink may be partitioned into resource blocks. Each resourceblock may cover 12 subcarriers in one slot and may include a number ofresource elements. Each resource element may cover one subcarrier in onesymbol period and may be used to send one modulation symbol, which maybe a real or complex value.

Subframe format 410 may be used for an eNB equipped with two antennas. ACRS may be transmitted from antennas 0 and 1 in symbol periods 0, 4, 7and 11. A reference signal is a signal that is known a priori by atransmitter and a receiver and may also be referred to as a pilot. A CRSis a reference signal that is specific for a cell, e.g., generated basedon a cell identity (ID). In FIG. 4, for a given resource element withlabel R_(a), a modulation symbol may be transmitted on that resourceelement from antenna a, and no modulation symbols may be transmitted onthat resource element from other antennas. Subframe format 420 may beused for an eNB equipped with four antennas. A CRS may be transmittedfrom antennas 0 and 1 in symbol periods 0, 4, 7 and 11 and from antennas2 and 3 in symbol periods 1 and 8. For both subframe formats 410 and420, a CRS may be transmitted on evenly spaced subcarriers, which may bedetermined based on cell ID. Different eNBs may transmit their CRSs onthe same or different subcarriers, depending on their cell IDs. For bothsubframe formats 410 and 420, resource elements not used for the CRS maybe used to transmit data (e.g., traffic data, control data, and/or otherdata).

The PSS, SSS, CRS and PBCH in LTE are described in 3GPP TS 36.211,entitled “Evolved Universal Terrestrial Radio Access (E-UTRA); PhysicalChannels and Modulation,” which is publicly available.

An interlace structure may be used for each of the downlink and uplinkfor FDD in LTE. For example, Q interlaces with indices of 0 through Q−1may be defined, where Q may be equal to 4, 6, 8, 10, or some othervalue. Each interlace may include subframes that are spaced apart by Qframes. In particular, interlace q may include subframes q, q+Q, q+2Q,etc., where qε{0, . . . , Q−1}.

The wireless network may support hybrid automatic retransmission (HARQ)for data transmission on the downlink and uplink. For HARQ, atransmitter (e.g., an eNB) may send one or more transmissions of apacket until the packet is decoded correctly by a receiver (e.g., a UE)or some other termination condition is encountered. For synchronousHARQ, all transmissions of the packet may be sent in subframes of asingle interlace. For asynchronous HARQ, each transmission of the packetmay be sent in any subframe.

A UE may be located within the coverage area of multiple eNBs. One ofthese eNBs may be selected to serve the UE. The serving eNB may beselected based on various criteria such as received signal strength,received signal quality, pathloss, etc. Received signal quality may bequantified by a signal-to-noise-and-interference ratio (SINR), or areference signal received quality (RSRQ), or some other metric. The UEmay operate in a dominant interference scenario in which the UE mayobserve high interference from one or more interfering eNBs.

Carrier Aggregation

LTE-Advanced UEs may use spectrum of up to 20 MHz bandwidths allocatedin a carrier aggregation of up to a total of 100 MHz (5 componentcarriers) used for transmission in each direction. For the LTE-Advancedmobile systems, two types of carrier aggregation (CA) methods have beenproposed, continuous CA and non-continuous CA. They are illustrated inFIGS. 5 and 6. Continuous CA occurs when multiple available componentcarriers are adjacent to each other (FIG. 5). On the other hand,non-continuous CA occurs when multiple available component carriers areseparated along the frequency band (FIG. 6). Both non-continuous andcontinuous CA aggregate multiple LTE/component carriers to serve asingle unit of LTE Advanced UE. According to various embodiments, the UEoperating in a multicarrier system (also referred to as carrieraggregation) is configured to aggregate certain functions of multiplecarriers, such as control and feedback functions, on the same carrier,which may be referred to as a “primary carrier.” The remaining carriersthat depend on the primary carrier for support are referred to asassociated secondary carriers. For example, the UE may aggregate controlfunctions such as those provided by the optional dedicated channel(DCH), the nonscheduled grants, a physical uplink control channel(PUCCH), and/or a physical downlink control channel (PDCCH). FIG. 7illustrates a method 700 for controlling radio links in a multiplecarrier wireless communication system by grouping physical channelsaccording to one example. As shown, the method includes, at block 705,aggregating control functions from at least two carriers onto onecarrier to form a primary carrier and one or more associated secondarycarriers. Next at block, 710, communication links are established forthe primary carrier and each secondary carrier. Then, communication iscontrolled based on the primary carrier in block 715.

Mutliflow

Presently, UEs receive data from one eNodeB. However, users on a celledge may experience high inter-cell interference which may limit thedata rates. Multiflow allows users to receive data from two eNodeBssimultaneously. It works by sending and receiving data from the twoeNodeBs in two totally separate streams when a UE is in range of twocell towers in two adjacent cells at the same time. The UE talks to twotowers simultaneously when the device is on the edge of either towers'reach (see FIG. 8). By scheduling two independent data streams to themobile device from two different NodeBs at the same time, multiflowexploits uneven loading in HSPA networks. This helps improve the celledge user experience while increasing network capacity. In one example,throughput data speeds for users at a cell edge may double. “Multiflow”is similar to dual-carrier HSPA, however, there are differences. Forexample, dual-carrier HSPA doesn't allow for connectivity to multipletowers to connect simultaneously to a device.

New Carrier Type

Previously, with LTE-A standardization carriers werebackward-compatible, which enabled a smooth transition to new releases.However, this meant that the carriers continuously transmitted commonreference signals (CRS), also referred to as cell-specific referencesignals, in every subframe across the bandwidth. Most cell site energyconsumption is caused by the power amplifier since the cell remains oneven when limited control signalling is being transmitted, causing theamplifier to continue to consume energy. CRS were introduced in release8 of LTE and are LTE's most basic downlink reference signal. They aretransmitted in every resource block in the frequency domain and in everydownlink subframe. CRS in a cell can be for one, two, or fourcorresponding antenna ports. CRS may be used by remote terminals toestimate channels for coherent demodulation. A new carrier type allowstemporarily switching off of cells by removing transmission of CRS infour out of five sub frames. This reduces power consumed by the poweramplifier. It also reduces the overhead and interference from CRS sincethe CRS won't be continuously transmitted in every subframe across thebandwidth. In addition, the new carrier type allows the downlink controlchannels to be operated using UE-specific Demodulation ReferenceSymbols. The New Carrier Type might be operated as a kind of extensioncarrier along with another LTE/LTE-A carrier or alternatively asstandalone non-backward compatible carrier.

LTE Plus Wi-Fi

With, WiFi Offload, the basic idea is whenever a WLAN access point isavailable, some or all of the traffic is routed through the WLAN accesspoint, thus offloading the cellular access. Mobile operators should beable to control which traffic is routed over WLAN and which one is kepton 3G/4G. For example, some IP flows (e.g., related to VoIP or otheroperators' services) can be maintained over 3G/4G to leverage its QoScapabilities, while IP flows related to “best-effort” Internet trafficcan be offloaded to WLAN. 3GPP introduced a Wi-Fi mobility framework inRelease 8 to enable seamless handover between 3G/4G and WLAN.

With interworking, the performance of each of the available links isestimated on a real-time basis, without any user intervention, and thebest possible link for the type of application the user is trying to useis selected. The performance estimation looks at a multitude ofparameters from an end-to-end perspective, covering not only thelast-mile air link to the users, but also all the way back to theInternet. Some of the parameters considered for the decision includesignal quality, available bandwidth, speed of the Internet connectivity,latency, as well as the operator policies regarding which apps/servicesare allowed to be moved to Wi-Fi and which are restricted to 3G/4G. So,the device continuously determines the most appropriate link andswitches between 3G/4G and Wi-Fi.

According to certain aspects, a user may be simultaneously connected toan LTE eNB and a Wi-Fi AP, which provide radio access links to transporta user's signaling and data traffic, as shown in FIG. 9. The eNB and theAP may be collocated or non-collocated. A user's data or signalingbearer may be served by either LTE or WiFi radio links. A bearerestablishes a “virtual” connection between two endpoints so that trafficcan be sent between them. It acts as a pipeline between the twoendpoints. Access to PDN services and associated applications isprovided to a UE by EPS bearers. A Default Bearer is typically isestablished during attachment and maintained throughout the lifetime ofthe connection. A dedicated bearer is used if the end-user usesconnectivity to a different Packet Data Network (PDN) to that providedby the default bearer, or if the end-user uses a different Quality ofService (QoS) to that offered by the default bearer. Dedicated bearersare configured to run in parallel to the existing default bearer.

According to certain aspects, a UE simultaneously connected to an LTEeNB and a Wi-Fi AP may perform offloading, within the UE, by dynamicallyswitching a location of an anchor point for PDCP processing of packetstransmitted over the WLAN.

Example Methods of Smart Processing of WWAN Packets Transmitted OverWLAN

Techniques for smart processing of wireless wide area network (WWAN)packets (e.g., long term evolution (LTE) packets) transmitted overwireless local area network (WLAN) interface (e.g., a WiFi interface)are described herein. According to certain aspects, a user equipment(UE) capable of communicating via at least first and second radio accesstechnologies (RATs) may dynamically switch to a location, within the UE,as an anchor point for processing packet data convergence protocol(PDCP) data packets based, at least in part, on operating states of thefirst and second RATs (e.g., the destination of the data packets, thedirect connection between the location of the anchor point and thedestination of the data packets, efficiency, etc. . . . ). The locationof the anchor point may be dynamically switched between the modemprocessor (e.g., a baseband processor) and the applications processor,within the UE, using inter-processor communication between the modemprocessor and the applications processor. The UE may route packetsreceived via at least one of the first and second RATs to thedynamically switched location of the anchor point.

A WLAN air interface is presently being considered as a carrier for WWANdata packets. Currently, when data packets are received by a UE (e.g.,UE 502) from a base station (BS) through the WLAN air interface, thedata packets are first transmitted to the modem processor and then tothe location of the data sink (the intended destination of the datapackets), for example, for long term evolution (LTE) packets, the sinkmay be in the Applications processor of the UE. This may causesignificant bus bandwidth utilization and/or increased powerconsumption. For example, if the sink of the packets is in theapplications processor, and if the packets are being received on theWLAN interface, the modem processor is kept up for the purpose ofprocessing the PDCP packets. This increases the power consumption in thedevice. For example, if only WiFi is active and the modem processor isnot receiving LTE packets, then the reason the packets are sent to theLTE modem is to be PDCP processed and then sent to the originaldestination. Transporting packets from the WiFi leg to the LTE modemprocessor and back may cause significant loading on the buses and on thedouble data rate (DDR) on-chip memory. The novel method and apparatusdiscussed herein, proposes that by knowing where the destination of thepackets is, the packets need not be transferred to the modem processorfirst, instead, the packets may be routed directly to the applicationsprocessor, in some cases.

As shown in FIGS. 10-13, if packets are received over the WWANinterface, the modem processor is kept up for processing the packets.

As used herein, a “sink” or “data sink” may refer to a device or part ofa device, that receives data or that is the intended destination for thedata. In the examples herein, the sink is typically in the UE, aparticular processor within the UE (e.g., such as an applicationsprocessor or a modem processor), or a tethered equipment to the UE. Thelocation of the sink may be dependent on the type of the data.

As used herein, “anchor point” or “anchor” may refer to a device, alocation within a device, or part of a device at which data received bythe device is first sent for processing/ordering. In the examplediscussed here, the device is typically a UE and the anchor is withinone of the processors of the UE, such as the applications processor orthe modem processor.

FIG. 10 illustrates a data path 1000 in which the UE 1006 receives datapackets from first and second RATs, for example a WLAN AP 1002 and anevolved Node B (eNB) 1004 (e.g., in a WWAN), where the data sink islocated in the Applications processor. As shown in FIG. 10, both WLANand WWAN RATs are actively communicating with the UE 1006. Data packetsfrom eNB 1004 are routed to the anchor point 1016 located at the modemprocessor 1010. Data packets from the WLAN AP 1002 are received by theUE 1006 at the WLAN air interface 1008 and also routed to the modemprocessor 1010 for the purpose of processing/reordering the datapackets. The data packets are then routed to the location of the datasink 1014, in this case, located at the applications processor 1012. Inthis scenario, both the applications processor 1012 and modem processor1010 may remain awake.

FIG. 11 illustrates a data path 1100 in which the UE 1006 receives datapackets from the WLAN AP 1002 and the eNB 1004, where the data sink 1114is located in the tethered equipment 1118. WiFi-only devices (e.g.,iPADs, laptops, e-books, and iPod touches) can use tethering to accessthe Internet even though there is no WiFi access point (AP) in theneighborhood. One way to access the Internet is to use a smartphone as amobile AP (MAP). The MAP may utilize its 3G/LTE interface to access theInternet. The tethered equipment 1118 may be a device tethered to the UE1006, which may be acting as a hotspot for the tethered equipment, forexample, via a USB interface, Bluetooth, WiFi interface, high speedinter-chip (HSIC), peripheral component interconnect express (PCIe),secure digital input/output (SDIO), or other interface. As shown in FIG.11, both the first and second RATs (WLAN AP 1002 and eNB 1004) areactive. Data packets from the WLAN AP 1002 may be received by the UE1006 at the WLAN air interface 1008 and forwarded to the anchor point1116 at the modem processor 1010. Data from the eNB 1004 is also routedto the modem processor 1010. Since the data sink 1114 is in the tetheredequipment 1118, the data packets may then be routed from the modemprocessor 1010 to the tethered equipment 1118 (e.g., via USB interface1120). The direct connection from the modem processor 1010 to the devicetethered 1118 to the UE 1006 allows the data packets to bypass theapplications processor 1012. In this scenario, the applicationsprocessor 1012 may be collapsed when not in use due to other traffic oruser activity. Alternatively, the applications processor 1012 may remainon due to other traffic or due to user activity.

FIG. 12 illustrates a data path 1200 in which the UE 1006 receives datafrom only the eNB 1004 while the WLAN may be inactive, and where thedata sink 1214 is located at the applications processor 1012. Since thedata packets from the eNB 1004 are processed at the modem processor, andsince the sink is in the applications processor 1012, both the modemprocessor 1010 and the applications processor 1012 remain active causingincreased load on the DDR memory and increased bandwidth and powerconsumption.

FIG. 13 illustrates a data path 1300 in which the UE 1006 receives datafrom only the eNB 1004 while the WLAN may be inactive, and where thedata sink 1314 is located at the tethered equipment 1118. Since the datapackets from the eNB 1004 are processed at the modem processor, themodem processor 1010 remains awake. In this scenario, the applicationsprocessor 1012 may be collapsed when not in use due to other traffic oruser activity. Alternatively, the applications processor 1012 may remainon due to other traffic or due to user activity.

FIG. 10-13 illustrates scenarios where the WWAN interface is active,and, thus, the modem processor 1010 remains awake. However, when theWWAN interface is inactive, if packets intended for the applicationsprocessor are being received only on the WLAN air interface 1008, themodem processor 1010 may be kept up for the purpose of processing PDCPpackets, which increases the power and bandwidth consumption of thedevice. FIGS. 14-15 illustrate scenarios where routing packets directlyfirst to the modem processor 1010 may be undesirable (e.g., inefficientin terms of bandwidth utilization and/or power consumption).

FIG. 14 illustrates a data path 1400 in which the WLAN air interface1008 is active and WWAN is inactive, and where the location of the datasink 1414 is at the tethered equipment 1118. As shown in FIG. 14, thedata packets received at the WLAN air interface 1008 are routed to theanchor point 1416 at the modem processor 1010 and then to the data sink1414 at the tethered equipment 1118 via the USB interface 1120. In thisscenario, although the applications processor 1012 can be collapsedunless active for other use cases, the modem processor 1010 remainsawake, even though there are no packets from the eNB 1004 for it toprocess.

FIG. 15 illustrates a data path 1500 in which the WLAN air interface1008 is active RAT and WWAN is inactive, and where the location of thedata sink 1514 is at the applications processor 1012. As shown in FIG.15, the data packets received at the WLAN air interface 1008 are routedto the anchor point 1516 at the modem processor 1010 and then to thedata sink 1514 at the applications processor 1012. In this scenario,both the modem processor 1010 and the applications processor 1012 remainawake, even though there are no packets from the eNB 1004 for it toprocess and the data sink is in the applications processor.

Therefore, techniques for dynamically selecting a location, within theUE, as an anchor point for processing packets based, at least in part,on operating states of the first and second RATs are desirable in orderto increase efficiency. For example, if data packets are being sent inthe WiFi RAT, the anchor point may be moved to the applicationsprocessor instead of sending the PDCP packets to the modem processorfirst.

According to certain aspects, techniques are provided herein fordynamically selecting a location, within a UE capable of communicatingvia first and second RATs, as an anchor point for processing packetsbased, at least in part, on operating states of the RATs.

FIG. 16 is a flow chart illustrating example operations 1600 forwireless communications, in accordance with certain aspects of thepresent disclosure. The operations 1600 may be performed, for example,by a UE (e.g., UE 120) capable of communicating via first and secondRATs (e.g., WWAN and WLAN). The operations 1600 may include, at 1602,switching to a location (e.g., between the applications processor andthe modem processor), within the UE, as an anchor point for processingpackets (e.g., PDCP processing) based, at least in part, on operationstates of the first and second RATs. As will be discussed in more detailbelow with respect to FIGS. 17-23, for example, the switching may bebased on whether the UE is actively communicating via the first RAT, thesecond RAT, or both. The switching may be further based on a destination(data sink) of the packets, based on whether a direct link existsbetween the applications processor, modem processor, and/or tetheredequipment, and/or based on which location may be more efficient forprocessing the packets.

At 1604, the UE may route packets received via at least one of the firstand second RATs to the dynamically switched location of the anchorpoint.

Optionally, at 1606, the UE may apply hysteresis when dynamicallyswitching to the location as the anchor point for processing packets.For example, hysteresis may be applied whenever there is a change inparameters that would force the change in the anchor point. Applyinghysteresis may include initializing a timer when parameters forswitching to a new location for an anchor point are met and routingpackets to the new location for the anchor point only after the timerhas expired and the parameters are still met.

Optionally, at 1608, the UE may transfer information between anchorpoint locations in preparation of changing anchor points. Optionally, at1610, the UE may communicate between a modem processor 1010 and anapplications processor 1012 to dynamically switch to the location as theanchor point. As a part of the switching, all information needed tosuccessfully switch processing of ensuing PDCP packets from the modemprocessor to the applications processor, or vice versa, have to behanded over to the other side. For example, the information may includecontext of the packets, one or more packets, the frame number, how manypackets were not properly received, or security information like PDCPdeciphering keys. The information may be periodically transferredbetween anchor point locations to speed processing after changing anchorpoints. This may also include some packets that were received out oforder and are pending processing because the preceding packet was notreceived. In this case, the transfer of information may be partial sincethe information being transferred may be a difference between whatinformation was transferred before and any new information, and whereinthe information comprises context information. This information may nothave been passed up to upper layers and, therefore, may be sent whenswitching the anchor from one layer to another. Thus, all theinformation that forms the PDCP state may be moved to the other side.

FIGS. 17-20 illustrate dynamically switching of anchor point locationbased on changing operating parameters of the system.

FIG. 17 illustrates an example data path 1700 for an example systemconfiguration and operation parameters where the UE is activelycommunicating via WLAN, WWAN is inactive, and the sink is in theapplications processor, in accordance with certain aspects of thepresent disclosure. In this scenario, the UE 1006 is no longer receivingLTE data packets from eNB 1004. Since there are no LTE packets and thedata sink 1714 is located in the applications processor 1012, the UE1006 may dynamically switch the location of the anchor point 1716 to theapplications processor 1012. By dynamically switching the location forprocessing data packets, data packets can be processed closest to theintended recipient, optimizing the data processing process.

According to certain aspects, inter-processor communication between themodem processor 1010 and the applications processor 1012 may performedas part of dynamically switching the location of the anchor point 1716,for example, between a PDCP Anchor Manager of the modem processor 1010and the applications processor 1012. The inter-processor communicationmay include a context 1722 handoff in order to obtain all informationneeded to successfully process incoming PDCP data packets. The contextinformation may include, for example, frame number, hyperframe number,number of packets, and/or packets that were received out of order andare pending processing because the preceding packet was not received.According to certain aspects, the context information may be sent priorto switching the location of the anchor point, for example,periodically. In this case, when dynamically switching the location ofthe anchor point, only context information that is new or that haschanged may be sent.

According to certain aspects, once the location of the anchor point 1716for PDCP data packet processing has been dynamically switched to theapplications processor 1012 and context handoff is complete, datapackets no longer have to be routed through the modem processor 1010 andthe modem processor 1010 can be collapsed.

FIG. 18 illustrates an example data path 1800 for an example systemconfiguration and operation parameters where the UE is activelycommunicating via WLAN, WWAN is inactive, and the sink is in a tetheredequipment, in accordance with certain aspects of the present disclosure.The tethered equipment 1118 may communicate via interface 1120. Althoughshown in FIG. 18 as a universal serial bus (USB) interface, theinterface 1120 may be any interference for tethered equipment, such asuniversal asynchronous receiver/transmitter (UART), peripheral componentinterconnect express (PCIE), WLAN, etc. As shown in FIG. 18, sincelocation of the sink 1814 is at the tethered equipment 1118, and nolonger in the applications processor 1012, the anchor point 1816 may beat the modem processor 1010—and the applications processor 1012 may becollapsed. Alternatively, as shown in FIG. 19, since the WWAN isinactive (e.g., the UE 1006 is not actively communicating with eNB1004), the location of the anchor point 1916 may be dynamically switchedto the applications processor 1012 if data processing in theapplications processor 1012 is more efficient as compared to the modemprocessor 1010. In that case, context 1922 information may be handedover, and processing may occur in the applications processor 1012. Datapackets may then be transmitted to its intended destination in thedevice tethered 1118 bypassing the modem processor 1010 and increasingefficiency of the system. In this case, the modem processor 1010 may becollapsed.

FIG. 20 illustrates an example data path 2000 for an example systemconfiguration and operation parameters where the UE is activelycommunicating via WLAN, WWAN is inactive, and a sink 2014 a is locatedin the applications processor 1012 and another sink 2014 b is located inthe tethered equipment 1118, in accordance with certain aspects of thepresent disclosure. As shown in FIG. 20, in this case, the anchor point2016 may be located at the modem processor 1010 and a router 2024 may beused to identify a destination of the packets and route the packets toeither the applications processor 1012 or the tethered equipment 1118.

FIG. 21 is an example truth table 2100 showing conditions for switchinganchor point locations, in accordance with certain aspects of thepresent disclosure. The various parameters shown in truth table 2100 aremerely exemplary. Other parameters may be used for determining when toswitch the location of the anchor point as well as to determine thelocation to be used as the anchor point. As shown in the example truthtable 2100, when the WWAN (e.g., eNB) is active, the location of theanchor point is always in the modem processor. When the WWAN is notactive, and the WLAN is active, if the data sink is in the applicationsprocessor 1012, then the location of the anchor point is always in theapplications processor 1012; however, if the data sink is in thetethered equipment, the location of the anchor point is based on otherfactors. For example, if there is no direct connection between the modemprocessor 1010 and the tethered equipment 1118 and/or no directconnection between the WLAN air interface and the modem processor 1010,then the location of the anchor is always in the applications processor1012. Alternatively, if a direct connection exists between WLAN airinterface and modem processor 1010 and between the modem processor 1010and the tethered equipment, then the location of the anchor point may bein whichever of the modem processor 1010 or the applications processor1012 is more efficient (e.g., uses less power to process the packets)for processing the packets.

According to certain aspects, hysteresis may be applied to dynamicallyswitching the location of the anchor point. The switching algorithm mayinclude a hysteresis whenever there is a change in parameters. Someparameters may force the change in anchor while some parameters may notimpose a stringent condition that necessitates change in anchor. Forexample, even if certain conditions/parameters are met for switching thelocation of the anchor point, the anchor may not immediate change untilcertain conditions of the hysteresis are met. For example, if theconditions remain satisfied for a given period of time (e.g., expiry ofa hysteresis time initialized when the conditions/parameters forswitching are met). In another example where hysteresis is beneficial,switching may involve transferring packets which may not have been givento the upper layers yet, thus, hysteresis may be useful beforecompleting a switch. One example of a forced change in anchor occurswhen the LTE RAT turns ON and receives data packets is a trigger thatwill cause the change of anchor point immediately. A forced change mayor may not use hysteresis when switching but, as discussed above, for asoft change hysteresis may be helpful. Another example where it would bebeneficial to apply hysteresis is in a configuration where theapplications processor is the anchor—assuming that the modem processoris more efficient than the applications processor in PDCP processing.This is shown in FIG. 21A where the WLAN is active and the sink is inthe applications processor, and the anchor point is at the applicationsprocessor. If the above configuration switched to the configurationshown in FIG. 21B due to removal of the sink in the applicationsprocessor and addition of a sink in the tethered equipment (i.e., a softchange), then it may be desirable not to switch the anchor to modemprocessor before the hysteresis timer expires.

FIG. 22 is a call flow 2200 diagram illustrating example operations forswitching an anchor point location, in accordance with certain aspectsof the present disclosure. As shown in the call flow 2200, at 1 and 2,the UE 1006 may be receiving incoming packets from both the WLAN AP 1002and the eNB 1004. At 3, the UE 1006 may route the packets to the modemprocessor 1010 where the anchor point is currently located. At 4, thepackets may be processed at modem processor 1010 (e.g., PDCPprocessing). Optionally, at 4 a, a periodic exchange of contextinformation may occur between the applications processor 1012 and themodem processor 1010. At 5, the UE 1006 may still be activelycommunicating with the WLAN AP 1002; however, the WWAN may be inactive.In this case, at 6, the control logic 2202 may determine a location fordynamically switching the anchor point. According to certain aspects,the control logic may be located in the modem processor 1010 or theapplications processor 1012, for example. The control logic may sendcontrol events to the WLAN, the modem processor 1010, and/or theapplications 1012 to coordinate the switching of the anchor point.According to certain aspects, the determination may be made based on anyparameters shown in truth table 2100 or based on other parameters and/orhysteresis. According to certain aspects, optionally, during atransition period for switching the location of the anchor point,incoming packets may be buffered, at 6 a, in the receiver (e.g.,WLAN/modem processor) while the switch is in progress. Once the switchis complete, the buffered packets may be routed to the new anchor pointlocation. This may avoid packets over the same RAT being received out oforder by the anchor point. Otherwise, the anchor point may reorder thepackets. At 6 b, the applications processor 1012 and the modem processor1010 may exchange any additional context information for processing thepackets. For example, any new or changed information since the periodicexchange of context information. At 7, the UE 1006 may route the packetsto the selected anchor point, for example, based on the informationreceived from the control logic 2202.

FIG. 23 is a flow chart illustrating example operations 2300 forwireless communications, in accordance with certain aspects of thepresent disclosure. The operations 2300 may be performed, for example,by a UE (e.g., UE 120) capable of communicating via first and secondRATs (e.g., WWAN and WLAN). The operations 2300 may include, at 2302,dynamically switching to a location, within the UE, as an anchor pointfor PDCP processing packets based, at least in part, on operating statesof the first and second RATs.

At 2304, the UE may route packets receives via at least one of the firstand second RATs to the dynamically switched location of the anchor pointbased, at least in part, on whether there is a direct link between aninterface of one of the first or second RAT and a modem processor, basedon whether the modem processor or an applications processor is moreefficient at processing the packets, and/or based on efficiency of theforwarding path. For example, forwarding packets rom WLAN to modemprocessor may include copying the packet data from one address space toanother, which may introduce additional bus bandwidth utilization andpotentially higher power usage (e.g., to operate the bus infrastructureat higher frequency).

At 2306, the UE may apply hysteresis when dynamically switching to thelocation as the anchor point for PDCP processing packets by initializinga timer and routing packets to the new location for the anchor pointonly after the timer has expired.

At 2308, the UE communicate, inter-processor, information between themodem processor and the applications processor to dynamically switch tothe location as the anchor point.

At 2310, the UE may periodically transfer information between the anchorpoint locations to speed processing after changing anchor points.

The various operations of methods described above may be performed byany suitable means capable of performing the corresponding functions.The means may include various hardware and/or software component(s)and/or module(s), including, but not limited to a circuit, anapplication specific integrated circuit (ASIC), or processor. Generally,where there are operations illustrated in figures, those operations mayhave corresponding counterpart means-plus-function components withsimilar numbering. For example, operations 1600 illustrated in FIG. 16correspond to means 1600A in FIG. 16A.

For example, means for transmitting, means for sending, means forsignaling, and means for transferring, may comprise a transmitter and/oran antenna(s) antenna(s) 352 of the UE 120 illustrated in FIG. 3. Meansfor receiving may comprise a receiver and/or antenna(s) 352 of the UE120 illustrated in FIG. 3.

Means for performing, means for switching, means for initializing, meansfor routing, means for processing, means for selecting, means forapplying, and/or means for determining may comprise a processing system,which may include one or more processors, such as the TX MIMO Processor366, the Transmit Processor 363, the Controller/Processor 380, and/orthe Receive Processor 358 of the UE 120 illustrated in FIG. 3.

In some case, rather than actually transmitting a frame, a device mayhave an interface to output a frame for transmission. For example, aprocessor may output a frame, via a bus interface, to an RF front endfor transmission. Similarly, rather than actually receiving a frame, adevice may have an interface to obtain a frame received from anotherdevice. For example, a processor may obtain (or receive) a frame, via abus interface, from an RF front end for transmission.

As used herein, the term “determining” encompasses a wide variety ofactions. For example, “determining” may include calculating, computing,processing, deriving, investigating, looking up (e.g., looking up in atable, a database or another data structure), ascertaining and the like.Also, “determining” may include receiving (e.g., receiving information),accessing (e.g., accessing data in a memory) and the like. Also,“determining” may include resolving, selecting, choosing, establishingand the like.

As used herein, a phrase referring to “at least one of” a list of itemsrefers to any combination of those items, including single members. Asan example, “at least one of: a, b, or c” is intended to cover a, b, c,a-b, a-c, b-c, and a-b-c., as well as any combination with multiples ofthe same element (e.g., a-a, a-a-a, a-a-b, a-a-c, a-b-b, a-c-c, b-b,b-b-b, b-b-c, c-c, and c-c-c or any other ordering of a, b, and c).

Those of skill in the art would understand that information and signalsmay be represented using any of a variety of different technologies andtechniques. For example, data, instructions, commands, information,signals, bits, symbols, and chips that may be referenced throughout theabove description may be represented by voltages, currents,electromagnetic waves, magnetic fields or particles, optical fields orparticles, or any combination thereof.

Those of skill would further appreciate that the various illustrativelogical blocks, modules, circuits, and algorithm steps described inconnection with the disclosure herein may be implemented as electronichardware, computer software, or combinations of both. To clearlyillustrate this interchangeability of hardware and software, variousillustrative components, blocks, modules, circuits, and steps have beendescribed above generally in terms of their functionality. Whether suchfunctionality is implemented as hardware or software depends upon theparticular application and design constraints imposed on the overallsystem. Skilled artisans may implement the described functionality invarying ways for each particular application, but such implementationdecisions should not be interpreted as causing a departure from thescope of the present disclosure.

The various illustrative logical blocks, modules, and circuits describedin connection with the disclosure herein may be implemented or performedwith a general-purpose processor, a digital signal processor (DSP), anapplication specific integrated circuit (ASIC), a field programmablegate array (FPGA) or other programmable logic device, discrete gate ortransistor logic, discrete hardware components, or any combinationthereof designed to perform the functions described herein. Ageneral-purpose processor may be a microprocessor, but in thealternative, the processor may be any conventional processor,controller, microcontroller, or state machine. A processor may also beimplemented as a combination of computing devices, e.g., a combinationof a DSP and a microprocessor, a plurality of microprocessors, one ormore microprocessors in conjunction with a DSP core, or any other suchconfiguration.

The steps of a method or algorithm described in connection with thedisclosure herein may be embodied directly in hardware, in a softwaremodule executed by a processor, or in a combination of the two. Asoftware module may reside in RAM memory, flash memory, ROM memory,EPROM memory, EEPROM memory, registers, hard disk, a removable disk, aCD-ROM, or any other form of storage medium known in the art. Anexemplary storage medium is coupled to the processor such that theprocessor can read information from, and write information to, thestorage medium. In the alternative, the storage medium may be integralto the processor. The processor and the storage medium may reside in anASIC. The ASIC may reside in a user terminal. In the alternative, theprocessor and the storage medium may reside as discrete components in auser terminal.

In one or more exemplary designs, the functions described may beimplemented in hardware, software, firmware, or any combination thereof.If implemented in software, the functions may be stored on ortransmitted over as one or more instructions or code on acomputer-readable medium. Computer-readable media includes both computerstorage media and communication media including any medium thatfacilitates transfer of a computer program from one place to another. Astorage media may be any available media that can be accessed by ageneral purpose or special purpose computer. By way of example, and notlimitation, such computer-readable media can comprise RAM, ROM, EEPROM,CD-ROM or other optical disk storage, magnetic disk storage or othermagnetic storage devices, or any other medium that can be used to carryor store desired program code means in the form of instructions or datastructures and that can be accessed by a general-purpose orspecial-purpose computer, or a general-purpose or special-purposeprocessor. Also, any connection is properly termed a computer-readablemedium. For example, if the software is transmitted from a website,server, or other remote source using a coaxial cable, fiber optic cable,twisted pair, digital subscriber line (DSL), or wireless technologiessuch as infrared, radio, and microwave, then the coaxial cable, fiberoptic cable, twisted pair, DSL, or wireless technologies such asinfrared, radio, and microwave are included in the definition of medium.Disk and disc, as used herein, includes compact disc (CD), laser disc,optical disc, digital versatile disc (DVD), floppy disk and blu-ray discwhere disks usually reproduce data magnetically, while discs reproducedata optically with lasers. Combinations of the above should also beincluded within the scope of computer-readable media.

The previous description of the disclosure is provided to enable anyperson skilled in the art to make or use the disclosure. Variousmodifications to the disclosure will be readily apparent to thoseskilled in the art, and the generic principles defined herein may beapplied to other variations without departing from the spirit or scopeof the disclosure. Thus, the disclosure is not intended to be limited tothe examples and designs described herein, but is to be accorded thewidest scope consistent with the principles and novel features disclosedherein.

What is claimed is:
 1. A method for wireless communications by a userequipment (UE) capable of communicating via at least first and secondradio access technologies (RATs), comprising: dynamically switching to alocation, within the UE, as an anchor point for processing packetsbased, at least in part, on operating states of the first and secondRATs, wherein the location of the anchor point is selected based, atleast in part, on whether the UE is actively communicating via the firstRAT, the second RAT, or both, and wherein the location of the anchorpoint is selected further based, at least in part, on a destination ofthe packets; and routing packets received via at least one of the firstand second RATs to the dynamically switched location of the anchorpoint.
 2. The method of claim 1, wherein the processing comprises atleast one of packet data convergence protocol (PDCP) processing orreordering of the packets, and wherein the switching is between anapplications processor and a modem processor.
 3. The method of claim 1,wherein the location of the anchor point comprises a modem processor oran applications processor.
 4. The method of claim 1, wherein thedestination of the packets comprises at least one of: an applicationsprocessor or a device tethered to the UE.
 5. The method of claim 4,wherein the device tethered to the UE is tethered via at a UniversalSerial Bus (USB), Bluetooth, wireless local area network (WLAN), highspeed inter-chip (HSIC), peripheral component interconnect express(PCIe), or a secure digital input/output (SDIO) interface.
 6. The methodof claim 1, wherein the location of the anchor point is selected based,at least in part, on whether there is a direct link between one of thefirst or second RAT and a modem processor.
 7. The method of claim 1,wherein the location of the anchor point is selected based, at least inpart, on whether there is a direct link between a modem processor and adevice tethered to the UE.
 8. The method of claim 1, wherein thelocation of the anchor point is selected based, at least in part, onwhether a modem processor or an applications processor is more efficientat processing the packets.
 9. The method of claim 1, wherein thelocation of the anchor point is selected based, at least in part, onefficiency of a forwarding path to a modem processor or an applicationsprocessor.
 10. The method of claim 1, further comprising applyinghysteresis when dynamically switching to the location as the anchorpoint for processing packets.
 11. The method of claim 10, whereinhysteresis is applied whenever there is a change in parameters thatwould force the change in the anchor point.
 12. The method of claim 1,further comprising applying hysteresis by: initializing a timer whenparameters for switching to a new location for an anchor point are met;and routing packets to the new location for the anchor point after thetimer has expired and the parameters are still met.
 13. The method ofclaim 1, further comprising transferring information between anchorpoint locations in preparation of changing anchor points.
 14. The methodof claim 13, wherein the information comprises at least one of: contextof the packets, one or more packets, or security information.
 15. Themethod of claim 13, wherein information is periodically transferredbetween anchor point locations to speed processing after changing anchorpoints.
 16. The method of claim 15, wherein a transfer of informationmay be partial since the information being transferred may be adifference between what information was transferred before and any newinformation, and wherein the information comprises context information.17. The method of claim 1, further comprising inter-processorcommunication between a modem processor and an applications processor todynamically switch to the location as the anchor point.
 18. The methodof claim 1, wherein: the first RAT comprises a wireless local areanetwork (WLAN); and the second RAT comprises a wireless wide areanetwork (WWAN).
 19. An apparatus for wireless communications by a userequipment (UE) capable of communicating via at least first and secondradio access technologies (RATs), comprising: at least one processorconfigured to: dynamically switch to a location, within the UE, as ananchor point for processing packets based, at least in part, onoperating states of the first and second RATs, wherein the location ofthe anchor point is selected based, at least in part, on whether the UEis actively communicating via the first RAT, the second RAT, or both,and wherein the location of the anchor point is selected further based,at least in part, on a destination of the packets; and route packetsreceived via at least one of the first and second RATs to thedynamically switched location of the anchor point; and a memory coupledwith the at least one processor.
 20. The apparatus of claim 19, whereinthe processing comprises at least one of packet data convergenceprotocol (PDCP) processing or reordering of the packets, and wherein theswitching is between an applications processor and a modem processor.21. The apparatus of claim 19, wherein the destination of the packetscomprises at least one of: an applications processor or a devicetethered to the UE.
 22. The apparatus of claim 21, wherein the devicetethered to the UE is tethered via at a Universal Serial Bus (USB),Bluetooth, wireless local area network (WLAN), high speed inter-chip(HSIC), peripheral component interconnect express (PCIe), or a securedigital input/output (SDIO) interface.
 23. The apparatus of claim 19,wherein the location of the anchor point is selected based, at least inpart, on whether there is a direct link between one of the first orsecond RAT and a modem processor.
 24. The apparatus of claim 19, whereinthe location of the anchor point is selected based, at least in part, onwhether there is a direct link between a modem processor and a devicetethered to the UE.
 25. The apparatus of claim 19, wherein the locationof the anchor point is selected based, at least in part, on whether amodem processor or an applications processor is more efficient atprocessing the packets.
 26. The apparatus of claim 19, wherein thelocation of the anchor point is selected based, at least in part, onefficiency of a forwarding path to a modem processor or an applicationsprocessor.